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(PHP 4, PHP 5, PHP 7, PHP 8)

session_nameLiefert und/oder setzt den Namen der aktuellen Session


session_name(?string $name = null): string|false

session_name() gibt den Namen der aktuellen Session zurück. Falls name angegeben wurde, aktualisiert session_name() den Namen der Session und gibt den alten Namen der Session zurück.

Wird ein neuer Session-Name (name) angegeben, ändert session_name() das HTTP-Cookie (und den Inhalt der Ausgabe, wenn session.transid aktiv ist). Nachdem das HTTP-Cookie gesendet wurde, erzeugt session_name() einen Fehler. session_name() muss vor session_start() aufgerufen werden, damit die Session ordnungsgemäß funktioniert.

Der Session-Name wird auf den Ausgangswert zurückgesetzt, der zu Beginn in gespeichert wurde. Deshalb muss session_name() bei jeder Anfrage aufgerufen werden (und bevor session_start() aufgerufen wurde).



Der Session-Name referenziert den Namen der Session, der in Cookies und URLs verwendet wird (z. B. PHPSESSID). Er sollte nur alphanumerische Zeichen enthalten und sollte kurz und beschreibend sein (z. B. für Benutzer mit aktivierter Cookie-Warnung). Wenn name angegeben wird und nicht null ist, wird der Name der aktuellen Session durch dessen Wert ersetzt.


Der Session-Name darf nicht nur aus Zahlen bestehen, sondern muss mindestens einen Buchstaben enthalten. Andernfalls wird jedesmal eine neue Session-ID erzeugt.


Gibt den Namen der aktuellen Session zurück. Wird name übergegeben und die Funktion aktualisiert den Session-Namen, wird der Name der alten Session zurückgegeben. Bei einem Fehler wird false zurückgegeben.


Version Beschreibung
8.0.0 name ist jetzt nullable (akzeptiert den NULL-Wert).
7.2.0 session_name() prüft den Session-Status; zuvor wurde nur der Cookie-Status geprüft. Somit war es zuvor möglich, dass session_name() nach session_start() aufgerufen wurde, was möglicherweise zum Absturz von PHP und zu anderem Fehlverhalten führen konnte.


Beispiel #1 session_name()-Beispiel

/* den Session-Namen auf WebsiteID setzen */
$name_vorher = session_name ("WebsiteID");
"Der vorhergehende Session-Name war $name_vorher<br />";

Siehe auch

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User Contributed Notes 10 notes

Hongliang Qiang
20 years ago
This may sound no-brainer: the session_name() function will have no essential effect if you set session.auto_start to "true" in php.ini . And the obvious explanation is the session already started thus cannot be altered before the session_name() function--wherever it is in the script--is executed, same reason session_name needs to be called before session_start() as documented.

I know it is really not a big deal. But I had a quite hard time before figuring this out, and hope it might be helpful to someone like me.
php at wiz dot cx
15 years ago
if you try to name a php session "" it gets converted to "example_com" and everything breaks.

don't use a period in your session name.
relsqui at chiliahedron dot com
15 years ago
Remember, kids--you MUST use session_name() first if you want to use session_set_cookie_params() to, say, change the session timeout. Otherwise it won't work, won't give any error, and nothing in the documentation (that I've seen, anyway) will explain why.

Thanks to brandan of who left a note under session_set_cookie_params() explaining this or I'd probably still be throwing my hands up about it.
Joseph Dalrymple
13 years ago
For those wondering, this function is expensive!

On a script that was executing in a consistent 0.0025 seconds, just the use of session_name("foo") shot my execution time up to ~0.09s. By simply sacrificing session_name("foo"), I sped my script up by roughly 0.09 seconds.
Victor H
8 years ago
As Joseph Dalrymple said, adding session_name do slow down a little bit the execution time.
But, what i've observed is that it decreased the fluctuation between requests.
Requests on my script fluctuated between 0,045 and 0,022 seconds. With session_name("myapp"), it goes to 0,050 and 0,045. Not a big deal, but that's a point to note.

For those with problems setting the name, when session.auto_start is set to 1, you need to set the on php.ini!
mmulej at gmail dot com
3 years ago
Hope this is not out of noting scope.

session_name('name') must be set before session_start() because the former changes ini settings and the latter reads them. For the same reason session_set_cookie_params($options) must be set before session_start() as well.

I find it best to do the following.

function is_session_started()
if (php_sapi_name() === 'cli')
return false;

if (version_compare(phpversion(), '5.4.0', '>='))
return session_status() === PHP_SESSION_ACTIVE;

return session_id() !== '';
if (!is_session_started()) {
tony at marston-home dot demon dot co dot uk
6 years ago
The description that session_name() gets and/or sets the name of the current session is technically wrong. It does nothing but deal with the value originally supplied by the value within the php.ini file.

$name = session_name();
is functionally equivalent to
$name = ini_get('');
is functionally equivalent to

This also means that:
$old_name = session_name('newname');
is functionally equivalent to
$old_name = ini_set('','newname');

The current value of is not attached to a session until session_start() is called. Once session_start() has used to lookup the session_id() in the cookie data the name becomes irrelevant as all further operations on the session data are keyed by the session_id().

Note that changing while a session is currently active will not update the name in any session cookie. The new name does not take effect until the next call to session_start(), and this requires that the current session, which was created with the previous value for, be closed.
tony at marston-home dot demon dot co dot uk
6 years ago
The description has recently been modified to contain the statement "When new session name is supplied, session_name() modifies HTTP cookie". This is not correct as session_name() has never modified any cookie data. A change in does not become effective until session_start() is called, and it is session_start() that creates the cookie if it does not already exist.

See the following bug report for details:
descartavel1+php at gmail dot com
1 year ago
Always try to set the prefix for your session name attribute to either `__Host-` or `__Secure-` to benefit from Browsers improved security. See

Also, if you have auto_session enabled, you must set this name in in your config (php.ini, htaccess, etc)
slave at codegrunt dot com
19 years ago
One gotcha I have noticed with session_name is that it will trigger a WARNING level error if the cookie or GET/POST variable value has something other than alphanumeric characters in it. If your site displays warnings and uses PHP sessions this may be a way to enumerate at least some of your scripts:

Warning: session_start(): The session id contains invalid characters, valid characters are only a-z, A-Z and 0-9 in /some/path/foo.php on line 666

I did not see anything in the docs suggesting that one had to sanitize the PHP session ID values before opening the session but that appears to be the case.

Unfortunately session_name() always returns true so you have to actually get to the point of assigning variables values before you know whether you have been passed bad session data (as far as I can see). After the error has been generated in other words.

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